Division 1 Approved Meter:

Approved meters will include the following attributes^f1:

• Power resolution of 1 mW or better,

• An available current crest factor of 3 or more at its rated range value, and,

• Lower bound on the current range of 10 mA or less,

The following attributes in addition to those above are suggested:

• Frequency response of at least 3 kHz, and,

• Calibration with a standard that is traceable to the U.S. National Institute of Standards and Technology (NIST),

It is also desirable for measurement instruments to be able to average power accurately over any user selected time interval (this is usually done with an internal math’s calculation dividing accumulated energy by time within the meter, which is the most accurate approach). As an alternative, the measurement instrument would have to be capable of integrating energy over any user selected time interval with an energy resolution of less than or equal to 0,1 mWh and integrating time displayed with a resolution of 1 second or less.